US Patent 8005367 Bi-directional optical module with improved optical crosstalk

The bi-directional optical module, which installs the receiver and the transmitter within one package, is disclosed with an improved optical crosstalk. The optical module provides a lens, a WDM filter and a photodiode (PD) on an axis of the single mode fiber coupled with the module, while, a laser diode (LD) in a position perpendicular to the optical axis. The WDM filter provides a multi-layered optical film on a primary surface and an edge in a side far from the LD and the (PD) makes an obtuse angle to the primary surface so as to prevent light from the LD and reflected at this edge from entering the PD.